Metering system for an agricultural machine

ABSTRACT

A metering system for a row unit for individual dispensing of grains comprises metering devices having a chamber for carrying grains, whereby a defined pressure level in the chamber is higher than ambient pressure. At least two metering elements establish a border to the chamber, whereby the metering elements are arranged within the housing so that they can be turned and the metering elements consist of cut-outs arranged along a curved path for picking up grains. At least one grain dispensing area is intended, which is defined by the chamber and the metering elements. The grain dispensing area includes a seed inlet element for transporting separated grains to a seed metering pipe to dispense the separated grains into a furrow, whereby a pressure application device is arranged at the seed inlet element or the seed metering pipe, to produce an air stream for the acceleration of the grains.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from German Application Nos. DE 10 2015101 255.3 filed Jan. 28, 2015 and DE 10 2015 101 256.1 filed Jan. 28,2015, the contents of which are incorporated herein by this reference.

FIELD

The present invention relates to a metering system for a row unit of anagricultural machine for an individual dispensing of granular materialwith the characteristics of the independent claim 1.

BACKGROUND

A variety of procedures, methods or machines are known in agriculturefor dispensing or distributing of seeds and fertilizer in granular formin a most even way on a farmland area. One kind of these machines iscalled a seed singulating machine. In the case of seed singulatingmachines, it is possible to single out grains by means of meteringdevices and to place these in regular intervals into a seed furrow.Generally, the seed furrow is produced by means of appropriate furrowingtools. In this way, almost all the seeds are provided with about thesame growing space, which ensures a uniform development of the plants.

In addition to the growing space, the selection of the best suited seedsfor the respective location is also crucial for the development of theplants. For example, there are some kinds of seeds that are bettersuited for rather dry and others for moist soil conditions. Some kindsof seeds are also better suited for heavy clay-like soils and others forrather light sandy soils. But since the soil conditions can often bevaried, in particular in the case of fields that cover a large area, itwould be advantageous if the kinds of seeds could be adapted within thefield according to the respective soil condition.

A variety of approaches to solve this are known from prior art. U.S.Pat. No. 6,672,228 B1, for example, describes a metering system for arow unit, wherein the metering system consists of two metering devices.For example, by means of a carousel, it is possible to supply differentkinds of seeds to the respective metering devices. After separating theseeds, the individual grains are placed in a seed pipe so that the seedscan be transported into the seed furrow. When there is a change of theseeds dispensing into the seed pipe from the first metering device tothe second metering device, these can be respectively moved in an axialdirection by means of a slider. The device is characterized in that whenindividual seed dispensing is performed in the first metering device,the second metering device does not perform any separation or viceversa, which means that only one respective metering device is active ata time.

Although it is thus possible to dispense different kinds of seeds, themoving of the metering device and of the carousel makes a quick changebetween the two metering devices or between the different kinds of seedsimpossible. At faster driving speeds and frequent changes of seeds, itis possible that there are inaccuracies in the seed dispensing due tothe time that is necessary for changing of the metering devices. Thedesign of the row unit with slider and carousel is also often veryextensive and thus also correspondingly costly. Furthermore, there is aproblem with the seed dispensing because it occurs in the seed pipe in afree fall. Due to vibrations and impacts which can occur in the row unitduring driving in the field, it is possible that the seeds are misplacedwithin the seed pipe or that the seeds collide within the seed pipe.This can also result in an uneven grain dispensing.

Another metering device by means of which seeds can be dispensed in ametered or individual manner is known from U.S. Pat. No. 7,765,943 B2.In this device, the seeds can be volumetrically metered by means of arotary valve or it can be separated by means of a metering unit. Thesupply of the seeds is regulated by a slide, whereby either a volumetricmetering or a separation of the seeds is performed, depending on theposition of the slide.

A further agricultural machine with two metering devices has been knownthrough the US-based company “Kinze Manufacturing Inc.”. In theirso-called Multi-Hybrid Planter 4900, two metering devices comprise onecommon seed dispensing area. The metering devices are operated by meansof low pressure systems respectively. After the grains are dispensedfrom one metering unit, they are placed into the seed furrow by means ofa free fall through a seed metering pipe. The switching between themetering devices or the kinds of seeds is performed, for example, bymeans of GPS-data. Yet, low pressure metering devices have thedisadvantage that they are very susceptible to dirt. In particular, dirtparticles can be sucked in by means of the low pressure in the meteringdevice, which can lead to malfunctions.

From WO 2014 113 803 A1, a further metering system for a row unit isknown. This metering system can be supplied with at least two differentkinds of seeds, whereby only one kind of seed can be dispensed with therespective metering device. However, this system has the disadvantagethat a quick switching between the kinds of seeds is not possiblebecause there is only one metering device. Rather, a respectivewaiting-time must be defined, in order to take into account the timethat is required for the grains to reach from the central seed tank tothe metering device. But such a system is very complex and it is alsoerror-prone if the timings are not chosen correctly.

Another metering system is known from WO 2014/205454 A1, which comprisestwo metering devices. The two metering devices are arranged with adistance between each other and both use the vacuum principle. It isthus possible that the seeds can be accommodated by the cut-outs of themetering elements. The seeds that are captured by the cut-outs can thensubsequently fall into one common seed metering pipe or into twoseparate seed metering pipes by means of gravity.

Other systems are also known from prior art, in which two streams ofseeds are connected by means of a Y-piece, whereby these are generallymetered volumetrically. Also, a connection of the streams of seeds isnot yet synchronized, which means that single grain dispensing cannot beguaranteed. It is also already known that, for example, micro granulesare added into a stream of individual grains. Up to now, a separatedgrain dispensing of these two compounds can also not be guaranteed inthis case. Additionally, the stream of individual grains can possibly beaffected, by means of which a sufficiently accurate seed dispensing canno longer be ensured.

SUMMARY

It is the objective of the present invention to present a meteringsystem for a row unit of an agricultural machine, which is arranged withat least two metering devices and/or metering units for an individualdispensing of the grains. The metering system should thereby be designedin such a way that a switching of the individual seeds dispensed fromthe at least one first to the at least one second metering device can beaccomplished as quickly as possible. At the same time, a bouncing of thegrains within the seed pipe should be prevented as much as possible.These objectives of the invention are achieved by means of thecharacteristics of the independent claim 1. Characteristics ofadvantageous developments of the invention are derived from thedependent claims. To achieve the above-mentioned objectives, the presentinvention presents a metering system for a row unit of an agriculturalmachine, preferably in the form of a seed singulating machine. The rowunit is connected to the agricultural machine by means of a frame,whereby the connection between the row unit and the frame isaccomplished by means of a support device. The support device can bedesigned, for example, in the form of a rhomboid.

The metering system consists of at least two metering devices, which canbe mounted onto the row unit. Alternatively, the at least two meteringdevices can also be set at a distance to the row unit and can bearranged to the machine and/or to the frame of the machine instead. Itis possible to supply the at least two metering devices with seeds froma seed reservoir via certain seed supply lines. Preferably at least twometering devices are supplied with different kinds of seeds, so that theseeds can be adapted to the different soils while driving on the field.

The at least two metering devices consist of at least one chamber forreceiving the grains for dispensing. Depending on the embodiment, the atleast two metering devices can consist of one common chamber or of onerespective chamber, whereby each one of the respective chambers issupplied with the seeds from the seed reservoir that are to bedispensed. If the metering devices consist of one common chamber, theyare separated by means of a dividing element. The purpose of thedividing element is to prevent the mixing of the different kinds ofseeds. Various elements can serve as dividers, preferably such thatprevent the different kinds of seeds from being mixed but that stillallow air to flow from one chamber into the next.

The at least one chamber is further characterized by a defined pressurelevel that is higher than the ambient pressure. Thus, the at least onechamber is pressurized, which can be accomplished by means of acorresponding pressure application device, for example, in form of ahigh pressure blower. It would also be possible to apply the oppositeside of the chamber with a lower pressure by means of a vacuum blower.In any case, the at least one chamber or the two chambers should bedesigned in such a way that the pressure level P1 in the chamber isgreater than the pressure level P2, which prevails in the area that isopposite of the chamber.

So if a pressure application device is mentioned in connection with thepresent description, it refers to any kind of high pressure or vacuumdevice, which can produce the desired high or low pressure within thechambers. Whether this high pressure or vacuum is produced by means of ablower or any other means is not of primary importance in the presentcontext.

The metering system according to the invention further consists of atleast two metering elements. The at least two metering elements arearranged in such a way within the housing of the at least two meteringdevices that they can be turned, or that the at least two meteringelements can rotate around a respective rotational axis. The at leasttwo metering elements can be preferably designed in a disc- and/or drum-and/or plate-like manner. It is also possible that the at least twometering devices are arranged with different metering elements. The atleast two metering elements are equipped with cut-outs, which arearranged along a curved path at regular intervals. These cut-outs can bedesigned in the shape of bore holes and/or elongated holes and/or slots,or the like, so that they can receive individual grains which weresupplied to the at least two respective metering devices. The cut-outscan further be arranged in different sizes and contours which areadapted to or chosen according to the respective materials that are tobe dispensed.

A border for at least one of the chambers is formed by the at least twometering elements, which means that the metering element is the borderof the respective chambers. The metering system further consists of atleast one grain dispensing area which is defined by the at least onechamber and by the at least two metering elements. A respectiveconnection to an area with a lower pressure level P2 than that of thechambers is achieved by means of the cut-outs. Thus, a pressuredifference occurs in the cut-outs of the at least two metering elements.The pressure difference assists the receiving of grains by therespective cut-outs. The grains which are in the chamber can thus bepicked up by the respective cut-outs of a metering element and can betransported to the at least one seed dispensing area by the rotation ofthe metering element. A pressure difference at the cut-outs cansubsequently be interrupted by means of appropriate interruptingelements, whereby the grains are then pushed out of the cut-outs intothe seed inlet element or into the seed metering pipe.

While only one grain dispensing area is formed for the metering systemaccording to the invention with one common chamber, two respective graindispensing areas are formed for the metering system with two chambers.

A separating device and/or a separating element can preferably bearranged between the grain pick up and the grain dispensing area. Theseparating device and/or the separating element ensures that excessgrains which are sticking to the cut-outs can be expelled. Thisseparating device can be designed in a variety of ways, whereby this onecorresponds to the preferred embodiment as it is known from EP 1 928 223B1, whereby also other separating devices would be possible.

The present object is characterized in that at least one graindispensing area is arranged at at least one seed inlet element forreceiving and transporting the separated grains to a seed metering pipein order to dispense the separated grains into a seed furrow in the soilwhich was prepared by means of soil cultivation tools. Hereby, the atleast one seed inlet element and/or the seed metering pipe is arrangedat a pressure application device by means of which an air stream for theacceleration of the grains can be produced.

If the metering system according to the invention forms at least onecommon chamber and thus also one common grain dispensing area, then onlyone seed inlet element is necessary. This seed inlet element is definedby the upper section of the seed metering pipe.

For a metering system with one common chamber and thus with one commonseed dispensing area this particularly means the following:

The invention intends that the at least two metering devices consist ofone common seed dispensing area, which means that different kinds ofseeds are separated by the respective metering devices and thentransported to the common seed dispensing area. Afterwards, theseparated material is led into the seed metering pipe, whereby the uppersection of the seed metering pipe is defined as the seed inlet element.The seed dispensing can be accomplished by means of only one respectivemetering device, or also by means of two metering devices. The advantageof such an arrangement is that it is possible to quickly switch betweenthe metering devices or between the kinds of seeds. Furthermore, the rowunit or the metering system can be designed in a simple way, since nofurther tools are needed for the switching or changing of the kinds ofseeds. A switching can be accomplished, for example, by means of aturning off of the motor of one of the metering devices. The common seeddispensing area can be pressurized with a defined pressure level that ishigher than the ambient pressure, for example, in form of some kind ofhigh pressure. The defined pressure level can be produced, for example,by means of a separate connector or by a connection with the chambers.By means of this defined pressure level, an air flow is produced withinthe seed metering pipe, by means of which the grains are acceleratedafter being released from the metering element and after being dispensedinto the seed metering pipe. This largely prevents a bouncing of thegrains within the seed metering pipe or at least reduces it to such anextent that it does not have any, or at least only an insignificantinfluence on the dispensing accuracy.

If the metering system according to the invention forms two chambers andthus also two seed dispensing areas, two corresponding seed inletelements are necessary. By means of a corresponding embodiment it ispossible to join the two seed inlet elements into one seed meteringpipe.

To accomplish this, the invention intends that the at least two meteringdevices and/or the at least two metering elements are arranged with somedistance between each other and that they are possibly not mounteddirectly on the row unit. The metering devices consist of one respectiveseed dispensing area with a seed metering pipe or with a seed inletelement that is arranged at it, which means that each seed dispensingarea is arranged with one respective seed inlet element. The two seedinlet elements are hereby united into one common seed metering pipewithin their further course. A Y-shaped element can preferably be usedas connecting piece. Other connecting pieces would also be possible,whereby their respective shape should be designed in such a way that theat least two seed inlet elements are united into a common seed meteringpipe. The joining into one seed metering pipe can also be performed atsome distance from the other. The seed inlet elements can also be madewith different lengths. The seed metering pipe can also be designed insuch a way that it forms a seed inlet element and that at least onesecond seed inlet element is connected to it, by means of which only oneadditional pipe would be needed. This connection can also be made in aY-shape and can be described as connecting piece. It is thus possiblethat the separated grains can be dispensed via one common seed meteringpipe into the furrow in the field that was produced by the soilcultivation tools.

The connection can be done directly after the metering devices or atsome distance to these. If, for example, the metering devices arearranged with some distance between the row units, a connection could bedone at the row unit. The advantage of such an arrangement is that it ispossible to quickly switch between the metering devices or the kinds ofseeds. Furthermore, the row unit or the metering system according to theinvention can be designed in a simple way, since no further tools areneeded for the switching or changing of the kinds of seeds. As in thecase with the embodiment with one common chamber or with one common seeddispensing area, a quick switching can be performed by turning off ofthe motor of the respective metering element.

Furthermore, it is possible that one seed dispensing area is pressurizedby a defined pressure level that is higher than the ambient pressure,for example, in the form of a high pressure blower. Comparable to theembodiment with one common chamber, the defined pressure level that ishigher than the ambient pressure can be produced by means of a separateconnector or by a connection of the chambers. By means of this definedpressure level, an air flow is produced within the seed metering pipe,by means of which the grains are accelerated after being released fromthe metering element and after being dispensed into the seed meteringpipe. Furthermore, this largely prevents a bouncing of the grains withinthe seed metering pipe or at least reduces it to such an extent that itdoes not have any or at least only an insignificant influence on thedispensing accuracy.

It is also possible that the at least two metering devices are designedin the form of vacuum metering devices, in which the pressure level P2is a vacuum and the pressure level P1 is greater than the pressure levelP2. In order that the grains can also be accelerated within the seedmetering pipe in this case, it is possible that the common seeddispensing area or at least one seed dispensing area from the two seeddispensing areas is equipped with a separate air supply. It would alsobe possible that the seed metering pipe or the at least one seed inletelement is arranged with a pressure application device. For example,this can be accomplished in the form of a Venturi or a ring nozzle, bymeans of which the grains are accelerated within the seed metering pipe.The air flow or the air pressure can preferably be regulated, by meansof which the speed of the grains within the seed metering pipe can beinfluenced.

The invention further intends that the air flow within the seed meteringpipe can be adapted. To accomplish this, different solutions arepossible. For one, the seed dispensing area can be actively connected toat least one chamber, so that the pressure level in the metering deviceon the side facing towards the grains is almost equal. It would also bepossible that the seed dispensing area is connected to the pressuregenerator or to the air supply pipe of the chambers by means of aseparate pressure connection. It is thus possible that there aredifferent pressure levels between the chamber and the at least one seeddispensing area or the one seed dispensing area. The additionalconnection may also consist of an adjusting element, by means of whichthe air stream or the air pressure within the seed metering pipe can beadjusted.

In one preferred embodiment, at least one seed dispensing area isconnected to a chamber or the seed inlet is arranged within the chamberof the metering device, by means of which the pressure in the chamber isalso used to produce the air stream within the seed metering pipe.

The cut-outs in the metering elements are arranged along a circular orcurved path, whereby the seed metering pipe or the seed inlet element isarranged at least partially in a tangential way towards at least one ofthe curved paths. The seed metering pipe consists of one seed inlet andone seed outlet, whereby these preferably feature a round cross section.But other cross sections would also be possible, for example, square orrectangular shapes. The cross section of the seed metering pipe can alsochange within its course. It can become bigger or smaller. It is therebypossible to change the speed of the grains within the seed meteringpipe. The seed metering pipe can also feature different radii, by meansof which the grains can be led along the seed metering pipe, which canprevent a bouncing of the grains. In the present object, the seedmetering pipe is curved in a sickle- and/or bow-shape at least in somesections.

In the case of one common chamber or one common seed dispensing area,the invention further intends that the seed metering pipe or the seedinlet is designed in such a way that it enlarges within the seeddispensing area and then narrows down in its further course. Theadvantage of this is that there is sufficient space for the grains inthe dispensing area to be securely received by the seed metering pipe.In the center of the widened area, it is possible, for example, toarrange for an intermediate piece which divides the seed metering pipe.In this way it is possible to achieve a suction effect by means of theair stream that occurs in the area of the grain dispensing, whichensures a smooth grain dispensing.

It can further be intended that the seed inlet is aligned at the disc insuch a way that the disc touches and slides on it. In the case of onecommon chamber or of one common seed dispensing area, this would meanthat the distance of the at least two metering elements towards eachother at the seed dispensing area is lesser than the diameter or thecross section of the seed metering pipe or of the seed inlet. In bothembodiments it would also be possible that the seed metering pipefeatures a round cross section, which would then be interrupted on theside that faces towards the disc. The grain dispensing of the meteringelement into the seed metering pipe can thus be greatly improved, sincepossibly interfering edges, which would otherwise be present between theseed metering pipe and the metering element are omitted in this way.

In the case of two chambers or of two seed dispensing areas, it wouldalso be possible that the metering element does not touch and slide onthe seed inlet element. But in order to prevent any edges of the seedinlet element at the metering element in such an arrangement, it can bealigned at an angle. It would also be possible that the seed inletelement is designed with a beveled edge and thus the thickness of theedge would also be reduced.

As mentioned earlier, the two metering devices and/or the at least twometering elements can consist of one common housing or can be arrangedwithin one common housing. Thus, the two metering elements would beintegrated in one constructional unit. The chambers of the meteringdevice are separated by a dividing wall in this case in order to preventa mixing of the different kinds of seeds. The kinds of seeds are storedin a seed reservoir and can be supplied to the chambers at any time. Thedividing wall is preferably designed in such a way that air can passthrough it. Thus, only one central air supply is needed for the at leasttwo metering devices, so that the piping effort of the machine can bereduced.

In the course of the seed metering pipe and/or of the at least one seedinlet element, at least one sensor element can be arranged for, by meansof which the grain dispensing or the grain transport can be monitored.The at least one sensor element is preferably designed as an opticalsensor element. The derived values of the at least one sensor or of thesensors can among others be used to adjust the speed of the meteringelements accordingly and thus it is possible to improve the dispensingaccuracy. In like manner, many different other applications are possibleas well.

The at least two metering devices may include many differentembodiments. Thus, metering devices which work according to the highpressure and/or the vacuum principle or which feature a combination ofthe high pressure and the vacuum principle are conceivable. Mechanicallyworking metering devices would also be possible, in which the grainseparation is performed, for example, by the so-called “finger pick up”.Also centrifugal-based metering devices are conceivable or possible, inwhich the acceleration of the grains can be achieved by the rotationspeed of the metering element.

The at least two metering devices can work according to the sameprinciple and may consist of basically the same setup. It is thuspossible that the metering devices feature a respective first area inwhich the grains are picked up by means of a pressure difference fromthe cut-outs in the metering element. The at least two metering devicesfurther consist of a second area in which a transport of the grainstowards the seed dispensing area is performed by means of the meteringelement. To accomplish this, a rotation of the metering element by meansof some kind of drive is necessary. This drive for the metering elementcan be a motor, an electric or hydraulic drive, etc. This area isequipped with a separating device and/or with separating elements. Oneof the purposes of the separating device or of the separating elementsis to expel excess grains from the cut-outs. This is done in such a waythat only one respective grain remains in the cut-outs. The at least twometering devices feature a third area, which is arranged with at leastone interrupting element for the interruption of the pressure differenceat the cut-outs. The at least one interrupting element can be designed,for example, in the form of a roller. An interruption of the pressuredifference has the effect, that the grains, which are located in thecut-outs, fall into the seed metering pipe by means of the seed inletelement. Alternatively, it is also possible that an air blast pushes thegrains out of the cut-outs. A fourth area is characterized in that thegrains and/or the air stream are redirected from a circular path andfrom a perpendicular air stream into a guided transporting direction anda guided air stream in the direction of the seed metering pipe.Furthermore, there is a fifth area that is arranged with a seed inlet ofthe seed metering pipe and with a section of the seed metering pipe fortransporting the grains towards a seed furrow.

In the case of one common chamber, at least two of the third, fourth andfifth areas or in the case of two chambers, the third, fourth and fiftharea, can hereby form the common seed dispensing area. For example, theareas thereby encompass an area that amounts to at least 75°. But biggeror smaller angles would also be possible.

The at least two metering devices can be arranged facing towards eachother in a mirror image-inverted way and/or twisted about theirrespective axes, or preferably the axis of the seed metering pipe and/orparallel relative to each other and/or at an angle and/or in acombination thereof. The sides with the chambers are preferably facingeach other.

The invention intends that at least one of the at least two meteringdevices or at least one metering element is arranged with a motor drive.Thus at least one of the at least two metering devices or at least onemetering element can be powered with a motor drive. Electrically,hydraulically or mechanically working drives would also be conceivable.It is further possible that transmission devices are used to transmitthe motion of the at least one powered metering device to the secondmetering device. Clutches or belts or transmissions or gear wheels canbe preferably used as transmission devices. It would also be possiblethat the at least two metering devices are arranged with a respectiveseparate drive, which means that each metering device can be powered bymeans of a separate drive. This would have the advantage that themetering devices could be operated at different speeds depending on thekind of seeds used. Additional aids, such as transmission gear boxes orthe like would not be necessary in this case.

In order to create an energy efficient row unit or an energy efficientmetering system, it would be necessary that the motor drives of themetering elements are coupled in such a way that the braking energy ofthe one first drive can be used as starting energy for the second driveand vice versa. In the same manner, the motion of one metering devicecould also be used as energy producer for the other metering device.

The at least two metering devices are coupled in such a way that anindividual grain dispensing can be performed into the seed inlet elementor into the seed metering pipe by means of at least one metering device,respectively. The speeds of the at least two metering elements areadapted relative to each other in such a way that when the graindispensing is switched from one metering element to the other, the graindispensing is synchronized, which means that the desired spacing of thegrains can also be maintained during a switching process. In order toimprove this ability, the at least two metering devices or the cut-outsof the at least two metering elements can be filled with grains untildirectly before the interrupting element or up to the seed dispensingarea. But there is only one grain dispensing or one interruption of thepressure difference at one metering device, respectively, which meansthat the interrupting element pushes the grains only out of the cut-outsof one metering element, respectively. In like manner, it is possiblethat for a simultaneous grain dispensing of the at least two meteringelements, respectively, these are synchronized in such a way that thegrains are dispensed into the seed inlet element alternately. Thus, inthe case of a simultaneous grain dispensing, the interrupting elementsof both chambers also have to be adapted relative to each other, whichwould mean that the interrupting elements would have to produce arespectively alternate interruption of the pressure difference. Forexample, this can be accomplished by means of a corresponding sensorarrangement in connection with a control device.

The desired switching between the kinds of seeds or between the at leasttwo metering devices is preferably done my means of GPS-data or by meansof any other satellite system or position detecting system. Theswitching positions could also be stored in a computer unit, and aswitching could be accomplished in this way. A manual switching by anoperator would likewise be possible. The switching between the at leasttwo metering devices is necessary in order that it is possible to switchbetween the different kinds of seeds.

In order to prevent a possible collision of the grains after a switchingof the grain dispensing from one metering device to the other, it ispossible that the metering elements of the at least two metering devicesare turning in the opposite direction of the respective other one, atleast for a certain time. This means that the metering element by meansof which a grain dispensing is to be done would turn, for example,clockwise, while the other metering element, which should no longerdispense any grains, would at least for a short time turn counterclockwise. A collision of the grains can be prevented in this way.Afterwards, a metering element could be fully deactivated by means ofturning off the motor. Due to the working together of the two meteringelements, different kinds of grains can be dispensed while driving onthe field.

Furthermore, the at least two metering devices can be designed in such away that the sides with the respectively lower pressure level areconnected to the respective chambers of the other metering device and/orto the air supply. It would also be possible that the areas with a lowerpressure level are in turn connected to a vacuum area of the pressureapplication device. It is further possible that the sides of the atleast two metering elements with the lower pressure level, or the sidesof the at least two metering elements that are facing away from thegrains, are equipped with some means so that the cut-outs in the areaswhere no grains are to be transported can be covered, or that thepressure difference can be stopped or reduced in these areas. Such areascould be located, for example, between the grain dispensing and thegrain pick up. But it is also possible that other parts could becovered, for example, in the case when no grains should be transportedor separated.

For example, the supply of the at least two metering devices with seedscan be done by means of a pneumatic conveyor system. An additionalcontainer for receiving and storing grains can also be arranged for eachmetering device. It would likewise be conceivable that at least onemetering device is supplied by a pneumatic conveyor system and thesecond metering device is supplied by an additional container. Thiswould be advantageous if, for example, much more would be needed fromone kind of seeds than from the other kind, so that the seeds with theheavy consumption would be supplied by a pneumatic conveyor system,wherein these seeds are provided in a big tank that is attached to themachine. The activation of the at least two metering devices couldlikewise be performed in such a way that when an interruption occursduring the supply of the seeds for the first metering device, the onesecond metering device will be automatically activated. Furthermore, theair supply for the pneumatic conveyor system could also be used tosupport the defined pressure level in the chamber.

In addition to the metering system, which is arranged at it, the rowunit also consists of furrowing tools, preferably two coulters which arealigned towards each other at an angle. They form a so-called doubledisc pair. But it would also be possible to use the present inventionwith a so-called single disc coulter or with a tine coulter. The seedmetering pipe is arranged, for example, between the two or next to theone disc, whereby the seed outlet on the other hand is arranged withinor directly next to the at least one outer contour of the at least onedisc. A catching element is further arranged directly behind thecoulters or the tines or it reaches into these and/or it is arrangednext to it and it is designed, for example, in the shape of a roller. Itis arranged in such a way that the stream of grains and/or the airstream is basically directed tangentially with regards to the outercontour or the catching element.

A change of direction of the grains occurs in the seed dispensing area,which means that the grains are redirected from a circular motion alonga curved path into a mainly tangential and/or straight direction withregards to the curved path. This is accomplished by means of a change ofdirection of the air streams which are directed as respectiveperpendicular air streams towards the cut-outs inside the chambers, intoa guided air stream. This air stream is directed along the seed meteringpipe and/or along the guiding element that is arranged at the at leastone seed dispensing area. Additionally, the guiding element features aguiding path which at least partially follows the same direction as theat least one seed inlet element. A good air stream can be produced inthis way, whereby the air stream can also be produced, for example, byan active connection with at least one chamber. But a separate airsupply would also be possible.

Furthermore, the curved path, the guiding element and the seed meteringelement are arranged in such a way that any element, such as grains,dirt particles or the like, which reach the grain dispensing area, areforcibly dispensed via the guiding path into the seed metering element.This reduces the susceptibleness to dirt tremendously. In order tofurther improve the susceptibleness to dirt, a push-out roller or apush-out element can be arranged for the at least two metering elementsor for the seed dispensing areas on the respective side that is facingaway from the grains. By means of these, any grains and/or dirtparticles that possibly remain in the cut-outs after the graindispensing, can be removed and dispensed into the seed metering pipe.

BRIEF DESCRIPTION OF DRAWINGS

Subsequently, the invention and its advantages will be further explainedby means of the embodiments and the attached figures. The ratio of thesizes of the individual elements in relation to each other in thefigures does not always correspond to the real size ratios since someshapes have been simplified and other shapes have been enlarged inrelation to other elements for better illustration.

FIG. 1 depicts a schematic side view of a row unit of an agriculturalmachine according to a first embodiment.

FIG. 2 depicts a perspective view of an embodiment of the meteringsystem according to the invention.

FIG. 3 depicts a cross sectional side view of one embodiment of themetering system according to FIG. 2.

FIG. 4 depicts a cross sectional top view of the metering systemaccording to FIG. 2.

FIG. 5 depicts a cross sectional front view of the metering systemaccording to FIG. 2.

FIG. 6A depicts an angled arrangement of the metering elements towardseach other in a simplified perspective view and FIG. 6B is a simplifiedtop view thereof.

FIG. 7 depicts a schematic side view of a row unit of the agriculturalmachine according to a second embodiment.

FIG. 8 depicts a side view of an embodiment of the metering systemaccording to the invention according to FIG. 7.

FIG. 9 depicts a front view of the metering system according to FIG. 7in a cross section.

FIG. 10 depicts a front view of the metering system according to FIG. 7in a cross section, wherein the metering elements touch and slide on theseed inlet elements.

DETAILED DESCRIPTION

For elements of the invention that are the same or that function in thesame way, identical reference numbers will be used in the FIGS. 1 to 10.Additionally, for a better overview, only reference numbers which areneeded for the description of the respective figure are depicted in theindividual figures. The depicted embodiments only representillustrations of how the metering system according to the invention canbe designed, and do not represent any final limitation.

FIG. 1 depicts a side view of a row unit 10 of an agricultural machinein the form of a seed singulating machine. Such machines are used inagriculture for an individual dispensing of granular grains such asseeds and/or fertilizer. Row unit 10 is connected to frame 14 of themachine via a support device 12 in form of a rhomboid. Row unit 10further consists of furrowing tools, which form in particular twocoulters 16 that are aligned at an angle towards each other. A catchingelement 18 is arranged subordinately to the coulters 16 or in such a waythat it reaches in between these. It is designed as a roller that shouldcatch and slow down the grains that are to be dispensed after they havebeen placed in the furrow. At the rear end of the row unit 10, tworollers 20 are arranged as furrow closing tools.

A metering system 22 is arranged at row unit 10 in the embodiment, whichconsists of two metering devices 24, 26. Metering system 22 is part ofrow unit 10 in the depicted illustration. But it would also be possiblethat it could be set at a distance from the row unit 10 and that itcould be arranged, for example, at the frame of the machine. A seedmetering pipe 28 is arranged at the lower end of metering system 22, bymeans of which the grains, which were separated by the metering devices24, 26, can be transported into the seed furrow. The section of the seedmetering pipe 28 that reaches into the metering elements can also bedescribed as seed inlet element 27.

Metering system 22 according to the invention is depicted in aperspective view in FIG. 2. Metering system 22 is made up of a front anda rear metering device 24, 26. In the depicted embodiment of FIG. 2, thetwo metering devices 24, 26 are constructed in an identical way. Butmetering devices 24, 26 are arranged facing towards each other in waythat they are twisted about their respective axes. Metering devices 24,26 consist of a respective multipart housing 30, which may comprise, forexample, a front and a rear housing part. The housing parts areconnected by means of hinges 32 and/or locking elements. Housing 30features a respective air inlet 38, by means of which its meteringdevices 24, 26 can be supplied with the appropriate pressure level. Themetering devices 24, 26 are supplied with material that needs to bedispensed in form of grains via a seed supply line 34 or via a notdepicted seed reservoir 36. The seeds are preferably different kinds ofmaterials. The supply of the metering devices 24, 26 can beaccomplished, for example, by means of a container or by means of apneumatic conveyor system that is attached to the row unit. In order tobe able to vary the amount of seeds that will be transported, additionalsliders 40 are arranged on the metering devices 24, 26. Slider 40 can beused to open or close the seed reservoir 36 in gradual stages. Eachmetering devices 24, 26 is powered by a drive motor 42. Electrical orhydraulical versions or motor drives can be used.

FIGS. 3, 4 and 5 depict different respective views of the combination ofthe two metering devices 24, 26 according to FIG. 2. Parts of housing 30or parts that are not needed for the description are accordingly notshown or depicted in cross section for a better understanding.

Metering system 22 consists of two metering devices 24, 26. They areconstructed in the same manner, but are arranged facing towards eachother in way that they are twisted about their respective axes. Themetering devices 24, 26 consist of one respective chamber or of onecommon chamber 44, which is supplied with the seeds that are to bedispensed or with the corresponding grains 46. In an embodiment with onecommon chamber 44, they are divided by means of a dividing element. Thisensures that the different kinds of seeds will not be mixed. Preferably,dividing elements are used which allow air to pass through.

Chambers 44 or the common chamber 44 is pressurized with a pressurelevel P1, which is produced, for example, by a pressure applicationdevice that is attached to the machine. For example, it is possible touse high pressure blowers for this purpose.

A metering element 48 is rotating within metering devices 24, 26, whichis designed in the form of a disc in the present embodiment. Cut-outs 52are arranged in regular intervals along at least one curved path 50 onthe respective metering element 48. The cut-outs 52 are made in the formof bore holes in the present example. But it is also possible that thecut-outs 42 are designed as elongated holes and/or slots, or the like.Furthermore, the cut-outs 52 in the metering devices 24, 26 can featuredifferent sizes and contours which can be adapted to or chosen accordingto the grain sizes that are to be dispensed. Metering element 48 forms arespective border to chamber 44, whereby a connection to the area with alower pressure level P2 is created by means of the cut-outs 52. Apressure difference is thus created at each one of the cut-outs 52. As aresult, grains 46 can be received in each cut-out 52. The grains whichwere picked up by the cut-outs 52 can be transported to one seeddispensing area 54 by the rotation of the metering element 48.

A separating device or a separating element 56 is arranged between theseed reservoir 36 and the seed dispensing area 54. These correspond tothe object of EP 1 928 223 B1, as was already mentioned earlier. But itwould also be possible to use a variety of other separating elements 56.By means of these separating devices 56, excess grains 46 and grainswhich are sticking to the cut-outs 52 can be expelled, so that only onerespective grain remains in the cut-outs 52.

The metering devices 22 consist of one common seed dispensing area 54,which means that different kinds of seeds are separated by the meteringdevices 24; 26, respectively. The grains which are held by the cut-outsare transported to the common seed dispensing area 54 by the rotation ofthe metering elements 48. By means of an interruption of the pressuredifference by interrupting elements 58, the grains are pushed into aseed metering pipe 28 that is arranged at the seed dispensing area 54via a seed inlet element 27. For example, the interrupting elements 58can be designed as a roller. The seed inlet element 27 defines a sectionof the seed metering pipe 28, which merges into the common seeddispensing area 54.

Just like the chambers 44, seed dispensing area 54 can also bepressurized. In the present embodiment, this is accomplished by means ofan active connection between the chambers 44 and the seed dispensingarea 54, which means that no further air supply is needed and thepressure level in the chambers 44 and in the seed dispensing area 54 isbasically the same.

By means of the air pressure within seed dispensing area 54, an airstream is created due to the lower pressure in the seed metering pipe28. After the grains 46 are released from the metering element 48, theyare picked up by the air stream, by means of which the grains 46 areactively accelerated within the seed metering pipe 28 by a seed inletelement 27. This largely prevents a bouncing of the grains 46 within theseed metering pipe 28 or at least reduces it to such an extent that itdoes not have any or at least only an insignificant influence on thedispensing accuracy.

The seed metering pipe 28 or the seed inlet 60 is designed in such a waythat it enlarges within the seed dispensing area 54 and then narrowsdown in its further course. The advantage of this is that there issufficient space for the grains 46 in the seed dispensing area 54 to besecurely received by the seed metering pipe 28.

A change of direction of the grains 44 occurs in the seed dispensingarea 54 from a circular motion along a curved path 50 into a mainlytangential and/or straight direction with regards to the curved path 50.This is accomplished via a redirecting of the air streams, which aredirected as respective perpendicular air streams 68 towards the cut-outs52 inside the chambers 44 into a guided air stream 66, which is guidedalong the seed metering pipe 28 and/or the guiding element 64 that isarranged to the seed dispensing area 54. Additionally, the guidingelement 64 features a guiding path 70, which follows at least partiallythe same direction as the seed metering pipe 28. A guided air stream 66can thus be produced. The air stream can also be produced by an activeconnection with at least one chamber 44. But a separate air supply wouldalso be possible.

Furthermore, the curved path 50, the guiding element 64 and the seedmetering pipe 28 are arranged in such a way that any element, such asgrains 44, dirt particles or the like, which reach the grain dispensingarea 54, are forcibly dispensed via the guiding path into the seedmetering pipe 28. This reduces the susceptibility to dirt tremendously.In order to further improve this, a push-out roller 58 is arranged forthe metering elements 48 or for the seed dispensing areas 54 on therespective side that is facing away from the grains 46. In this way, anygrains 46 and/or dirt particles that possibly remain in the cut-outs 52after the grain dispensing, can be removed and dispensed into the seedmetering pipe 28 via the seed inlet element 27.

In the embodiment of FIGS. 3 to 5, only one respective grain dispensingis performed by only one metering device 24, 26. But the other meteringdevice 24, 26 is filled with grains 44 until directly before the seeddispensing area 54 or up to the interrupting element. This enables aquick switching between the metering devices 24, 26, so that themetering devices 24, 26 do not need any waiting time before they candispense the grain.

In FIGS. 1 to 5, the metering devices 24, 26 are twisted about theirrespective axes and arranged in parallel with an offset between eachother. In FIGS. 6A and 6B, another possible arrangement of the meteringdevices 24, 26 or of the metering elements 48 is made evident in aperspective view and in a top view.

The metering elements 48 are arranged at a respective angle towards eachother. A seed metering pipe 28, which consists of a seed inlet 60 mergestowards the lower right side. The upper section of the seed meteringpipe 28 defines the seed inlet element 27. The metering elements 48directly touch and slide on the respective seed inlet 60 or the seedmetering pipe 28. This means that the distance of the metering elements48 towards each other at the seed dispensing area 54 is less than thediameter of the seed metering pipe 28. As a result, the respectivebow-shaped contour 62 of the seed metering pipe 28 is interrupted on theside that is facing towards the metering elements 48. The advantage ofthis is that there are no edges of the seed metering pipe 28 that touchthe metering element 48. This leads to an improvement of the graindispensing.

FIG. 7 also depicts a side view of an embodiment of a row unit 10according to a second design form. This design form also consists ofmetering system 22. While one of the two metering systems is a directpart of row unit 10, the other one is intended to be mounted onto frame14. One respective seed inlet element 27 is assigned to both meteringdevices 24, 26. The two seed inlet elements 27 can be connected to oneseed metering pipe 28 by means of a connecting piece 29. The connectingpiece 29 is designed in a Y-shape. But a variety of other connectingpieces or connecting possibilities would also be conceivable. But in anycase, the connecting pieces are designed in such a way that the at leasttwo seed inlet elements 27 are joined into a common seed metering pipe28. The joining of the respective seed inlet elements 27 is done at rowunit 10, whereby other locations would also be possible or conceivable,in particular directly after the metering devices 24, 26. The advantageof such a joining is that only one respective seed metering pipe 28 hasto be placed at the row units 10 and not two seed inlet elements 27.

Metering system 22 is depicted in a side view in FIG. 8. Metering system22 is made up of a front and a rear metering device 24; 26. In thedepicted embodiment of FIG. 8, the two metering devices 24, 26 areconstructed in an identical way. But they are arranged towards eachother in way that they are twisted around their respective axes.Metering devices 24; 26 consist of a respective multipart housing 30,which may, for example, comprise a front and a rear housing part. Thehousing parts are connected by means of hinges 32 and/or lockingelements. Housing 30 features a respective air inlet 38, so that themetering devices 24, 26 can be supplied with the appropriate pressurelevel. The metering devices 24, 26 are supplied with material that needsto be dispensed in form of grains via a seed supply line 34 or via aseed reservoir 36 which is not depicted. The materials are preferably ofdifferent kinds. The supply of the metering devices 24, 26 can beaccomplished, for example, by means of a container or by means of apneumatic conveyor system that is attached to the row unit. In order tobe able to vary the amount of seeds that will be transported, additionalsliders 40 are arranged on the metering devices 24, 26. Sliders 40 canbe used to open or close the seed reservoir 36 in gradual stages. Eachmetering device 24, 26 is powered by a drive motor 42. This can be amechanical, an electrical or hydraulic drive, etc.

FIG. 9 depicts the arrangement of the two metering devices 24, 26 in afrontal cross section. Parts of housing 30 or parts that are not neededfor the description are accordingly not shown or depicted in crosssection for a better understanding.

Metering system 22 consists of two metering devices 24, 26. In thedepicted embodiment, the two metering devices 24, 26 are constructedmainly in an identical way. Furthermore, the metering devices 24, 26 arearranged towards each other in way that they are twisted about theiraxes or about the axis of the seed metering pipe 28. The meteringdevices 24, 26 each consist of one respective chamber 44. Each chamber44 can be supplied with seeds that are to be dispensed or withcorresponding grains 46.

Chambers 44 are pressurized with a respective pressure level P1, whichis produced, for example, by a pressure application device in form of ahigh pressure or vacuum blower that is attached to the machine.

A metering element 48 is rotating within each of the metering devices24, 26, which are designed in the form of a disc in the presentembodiment. The respective metering element 48 consists of cut-outs 52that are arranged in regular intervals along at least one curved path50. The cut-outs 52 are made in form of bore holes. But it is alsopossible that the cut-outs are designed as elongated holes and/or slotsor the like. Furthermore, the cut-outs 52 in the metering devices 24, 26can feature different sizes and contours which can be adapted to orchosen according to the grain sizes that are to be dispensed. Meteringelements 48 form a border to chamber 44, respectively. A respectiveconnection to an area with a lower pressure level P2 is achieved bymeans of the cut-outs 52. A pressure difference is thus created at eachone of the cut-outs 52. Among other things, the pressure differenceassists the receiving of grains by the respective cut-outs 52. Thepicked up grains can subsequently be transported to one seed dispensingarea 54 by the rotation of the metering elements 48.

The metering devices 22 consist of one respective seed dispensing area54, which means that different kinds of seeds are separated by therespective metering devices 24, 26 and then transported to the seeddispensing area 54 by the rotation of the metering elements 48. Thegrains that are held in the cut-outs 52 are subsequently released into aseed inlet element 27 that is arranged at the seed dispensing area 54and/or into a seed metering pipe 28 by means of an interruption of thepressure difference by interrupting elements 58. The interruptingelements 58 can be designed, for example, in the form of a roller.Depending on the embodiment, the interrupting elements 58 can workalternately, so that one respective grain is released from the firstseed dispensing area and subsequently one grain from the second seeddispensing area into the seed metering pipe 28. It is also possible thatonly one interrupting element 58 of one chamber 44 is active, by meansof which only the same kind of seeds can be dispensed into the ground.

Just like the chambers 44, seed dispensing area 54 can also bepressurized. In the present embodiment, this is accomplished by means ofan active connection between the chambers 44 and the seed dispensingarea 54. This means that no further air supply is needed and thepressure level in the chambers 44 and in the seed dispensing area 54 isbasically the same.

By means of the air pressure that is present in at least one seeddispensing area 54, an air stream is created due to the lower pressurein the seed metering pipe 28. After the grains 46 are released from themetering element 48 they are picked up by the air stream. Thus, thegrains 46 are actively accelerated within the seed metering pipe 28.Furthermore, this largely prevents a bouncing of the grains 46 withinthe seed metering pipe 28 or at least reduces it to such an extent thatis has no or at least only an insignificant influence on the dispensingaccuracy.

The seed metering elements 27 are arranged at an angle towards meteringelement 48, so that their seed inlet 40 also features an angle towardsit. In order to avoid interfering edges or the like and to keep thedistance between metering element 48 and seed inlet 40 as small aspossible, seed inlet elements 27 are beveled on the respective side thatis facing the metering elements 48.

FIG. 10 depicts a front view of the metering system 22 in a crosssection, wherein the metering elements 48 directly touch and slide onthe seed inlet elements 27. By means of such an arrangement, edgesbetween metering elements 48 and the seed inlet elements 27 areprevented. Thus, the grain dispensing can be improved accordingly. Thediameter of the seed inlet elements 27 in the seed dispensing area isfurthermore adapted to correspond to the touching and sliding, which canalso improve the grain intake by means of the seed inlet elements 27.The invention was described with reference to a preferred embodiment.But it is still possible for a skilled person to make adaptations andchanges to the invention without leaving the scope of protection of thefollowing claims.

LIST OF REFERENCE SIGNS

10 row unit

12 support device

14 frame

16 coulter

18 catching element

20 roller

22 metering device

24 front metering device

26 rear metering device

27 seed inlet element

28 seed metering pipe

29 connecting piece

30 housing

32 hinge

34 seed supply line

36 seed reservoir

38 air supply

40 slider

42 motor

44 chamber

46 grains

48 metering element

50 curved path

52 cut-outs

54 grain dispensing area

56 separating device, separating element

58 push-out roller

60 seed inlet

62 bow-shaped contour

64 guiding elements

66 guided air stream

68 perpendicular air stream

70 guiding path

1. A metering system for a row unit of an agricultural machine for anindividual dispensing of grains such as seeds, fertilizer or the like,comprising at least two metering devices, whereby the at least twometering devices consist of at least one chamber for carrying the grainsthat are to be dispensed, and whereby there is a defined pressure levelin the at least one chamber that is higher that the ambient pressure, atleast two metering elements that establish a border to the at least onechamber, whereby the at least two metering elements are arranged in sucha way within the housing of the at least two metering devices that theycan be turned and that they consist of cut-outs, which are arrangedalong a curved path at regular intervals for picking up grains, at leastone grain dispensing area, which is defined by the at least one chamberand by the at least two metering elements, characterized in that atleast one grain dispensing area is arranged at at least one seed inletelement for receiving and transporting the separated grains to a seedmetering pipe in order to dispense the separated grains into a seedfurrow in the soil which was prepared by means of soil cultivationtools, whereby a pressure application device is arranged for the atleast one seed inlet element and/or the seed metering pipe, by means ofwhich an air stream for the active acceleration of the grains can beproduced, and whereby the at least one seed dispensing area consists ofan air connection to the at least one chamber and/or to a pipe of theair supply of the at least one chamber and/or to the pressureapplication device and/or the seed metering pipe reaches into the atleast one chamber.
 2. A metering system according to claim 1, in whichthe pressure application device is designed in the form of a Venturinozzle and/or a ring nozzle.
 3. A metering system according to claim 1,in which the metering devices work according to the high pressureprinciple and/or according to the vacuum principle and/or according tothe centrifugal principle.
 4. A metering system according to claim 1, inwhich two respective seed inlet elements are intended for at least twochambers, which will be or which are joined by means of a connectingpiece to one seed metering pipe, whereby the connecting piece isdesigned in a Y-shape.
 5. A metering system according to claim 1, inwhich the metering elements are designed or formed in a disc- and/ordrum- and/or plate-like manner, whereby the cut-outs are designed in theshape of bore holes and/or elongated holes and/or slots.
 6. A meteringsystem according to claim 5, in which the cut-outs are arranged along acurved path on the metering elements and the at least one seed inletelement is arranged at least partially in a tangential way towards theat least one of the curved paths of the at least two metering devices.7. A metering system according to claim 1, in which the at least twometering devices consist of one common housing and the at least onechamber is divided by a dividing wall.
 8. A metering system according toclaim 7, in which a guiding element is arranged for the at least twometering devices, wherein the guiding element features a guiding pathwhich is aligned at least partially parallel to the seed metering pipeand by means of which a change of direction of the grains can beaccomplished, from a circular direction along a curved path into abasically linear and/or straight direction towards the seed meteringpipe.
 9. A metering system according to claim 7, in which the at leasttwo metering devices and/or the at least two metering elements can bearranged facing towards each other in a basically mirror image-invertedway and/or in a way in which they are twisted about their respectiveand/or parallel towards each other with an offset and/or at an angleand/or in a combination thereof.
 10. A metering system according toclaim 9, in which the at least two metering elements are or can beturned at a different and/or at the same speed.
 11. A metering systemaccording to claim 10, in which the movement of the at least one firstmetering element can be transmitted to the at least one second meteringelement by means of transmission devices, preferably by means ofclutches and/or belts and/or transmissions and/or gear wheels.
 12. Ametering system according to claim 10, in which the respective speeds ofthe at least two metering elements are adapted relative to each other insuch a way that when the grain dispensing is switched from the at leastone metering element to the at least one second metering element, adesired interval between the dispensed grains is maintained.
 13. Ametering system according to claim 7, in which the cut-outs of themetering elements of the at least two metering devices (are filled withgrains until directly before the interrupting element and/or up to theseed dispensing area.
 14. A metering system according to claim 7, inwhich during a switching of the individual grain dispensing from onemetering device to another metering device, the metering element of oneof the metering devices is rotating at least for a moment in theopposite direction of the other one.
 15. A metering system according toclaim 7, in which a switching of the individual grain dispensing fromone metering device to another metering device is performed on the basisof GPS-data and/or position detecting systems and/or by means of datathat is stored on a computer and/or in a manual way.
 16. A meteringsystem according to claim 7, in which the at least two chambers and/orthe seed reservoir are supplied with different kinds of seeds.
 17. Ametering system according to claim 1, in which the seed metering pipeconsists of a seed inlet which touches and slides on the at least twometering elements and/or in which the distance of the metering elementstowards each other is lesser than the diameter and/or the width of theseed metering pipe.